Commit a55d581f authored by Committed by Ben Gamari
Fix Windows stack allocations.
On Windows we use the function `win32AllocStack` to do stack allocations in 4k blocks and insert a stack check afterwards to ensure the allocation returned a valid block. The problem is this function does something that by C semantics is pointless. The stack allocated value can never escape the function, and the stack isn't used so the compiler just optimizes away the entire function body. After considering a bunch of other possibilities I think the simplest fix is to just disable optimizations for the function. Alternatively inline assembly is an option but the stack check function doesn't have a very portable name as it relies on e.g. `libgcc`. Thanks to Sergey Vinokurov for helping diagnose and test. Test Plan: ./validate Reviewers: bgamari, erikd, simonmar Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #14669 Differential Revision: https://phabricator.haskell.org/D4343
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